1. Field of the Invention
The present invention relates to a lid member with a waterproofing function for an electronic device, and more particularly to a structure for sealing so as to prevent water droplet from intruding into an inner portion of the electronic device, for example, a mobile phone terminal.
Accordingly, the lid member with the waterproofing function according to the present invention is preferably utilized as a seal structure of a connector portion of the waterproofing electronic device.
2. Description of the Conventional Art
Conventionally, a connector lid for opening and closing a connector is provided in a portable terminal.
In other words, the connector lid for opening and closing a communication port for the connector is fixed and retained to a housing (a case) side by a flexible band portion which is formed as a band shape or a circular shape.
Further, a small rib-shaped seal ring portion is formed in a peripheral side surface of the connector lid occluding the connector over its whole periphery.
As a result, the connector lid carries out a function of sealing the communication port for the connector in a watertight manner.
This kind of connector lid is specifically structured, for example, such that a waterproofing plug is integrally formed in the connector lid according to an ultrasonic welding, the waterproofing plug being obtained by insert molding a rubber packing which is formed by a silicone rubber, around a plug member which is formed in an inner side of the lid member formed by a polycarbonate (Japanese Unexamined Patent Publication No. 2006-84438).
However, since the waterproofing plug exists in the inner side of the connector lid, there has been brought about a problem that a thickness of a whole of the connector lid is increased, and a manufacturing cost is increased.
Consequently, there has been offered a suggestion that a thin waterproofing structure of the connector lid is achieved by integrating a seal portion 300 which is a waterproofing member and is made of a rubber-like elastic material, with a connector lid main body 2 which is made of a resin material, as shown in FIG. 6 (Japanese Unexamined Patent Publication No. 2010-186562).
In other words, this kind of lid member with the waterproofing function is constructed by a projection portion 21 which is integrally formed in one surface of a resin main body 2 of a lid member opening and closing an opening portion 11 formed in a housing 1 and is accommodated in the opening portion 11, and a seal portion 300 which is integrally formed in an outer peripheral surface 211 of the projection portion 21 and is provided with an annular projection portion 310 coming into close contact with a peripheral surface 12 of the opening portion 11.
However, the portable terminal device is going to be requested to be lightened and thinned more and more, and the connector lid provided in the side surface of the portable terminal device is necessarily going to be downsized.
As a result, when this kind of lid member with the waterproofing function is inserted into the opening portion 11 formed in the housing 1, the seal portion 300 is deformed by an end portion 13 of the housing 1, as shown in FIG. 7.
Since the connector lid is downsized, there has been brought about a problem that the lid member is pushed back and can not be capped as well as an inserting amount of the lid member with the waterproofing function in relation to the opening portion 11 can not be sufficiently secured.
Accordingly, there has been made an attempt to reduce an amount at which the seal portion 300 comes into contact with the peripheral surface 12 of the opening portion 11 (a crushing margin of the seal portion 300), however, a contact pressure of the seal portion 300 in relation to the peripheral surface 12 is lowered, so that it has been hard to secure a stable seal performance.